JP2017227614A - Surface checkup method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface checkup method by which the time taken to check up can be minimized and the productivity can be maintained at a satisfactory level.SOLUTION: A surface checkup method comprises a first step of emitting checkup light, a second step of passing the light emitted by the first step through plural slits to generate checkup light of a fringe pattern and a third step of irradiating in a prescribed range and at a prescribed incidence angle the surface of the checkup object given the specularity by having gone through the second step. By causing the surface of the checkup object to reflect the fringe-pattern image and observing this reflected image, the surface state of the checkup object can be checked up.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a surface inspection method for inspecting the state of a surface of an object to be inspected having a specularity.

  Conventionally, various surface inspection methods for inspecting the surface state of an object to be inspected are known and used in many applications. For example, the surface state measuring apparatus shown in Patent Document 1 and the surface shown in Patent Document 2 are used. A strain measuring device and a measuring method are known.

  JP 2002-98515 A   JP 2010-216870 A

  First, in the surface state measuring apparatus described in Patent Document 1, the grating 3 is arranged at an angle different from that of the glass substrate 4 so that the reflected light from the grating 3 does not enter the image sensor 8, and the bandpass A technique is disclosed in which only light having a wavelength of around 313 nm is guided to the image sensor 8 by the filter 6 so as not to be affected by reflected light from the back surface of the glass substrate 4. The inspection light is transmitted twice through 3 to create a moire image, and the surface property of the object to be inspected is to be measured three-dimensionally based on the distortion of the moire image.

  Therefore, if the technique of this patent document 1 is used, the surface property of the object to be inspected can certainly be measured three-dimensionally. For this purpose, the distance between the lattice and the object to be inspected is changed a plurality of times. In addition, it has been pointed out that the image reading operation must be performed every time, and the inspection time is inevitably long, and when it is used in the production technology, the productivity is deteriorated. Furthermore, since the technique described in Patent Document 1 requires parallel light, it is difficult to widen the detection area because the irradiation range depends on the size of the lens that produces the parallel light. However, since the size of the lens becomes enormous, the problem of becoming a large-scale device has been pointed out, and a solution is desired.

  On the other hand, in the surface strain measuring apparatus and measuring method described in Patent Document 2, linear light generating means 2 for generating linear diffused light to the object to be measured 1 and linear on the surface of the object to be measured 1 Imaging means 3 that captures a mirror image of diffused light, linear light generating means 2, moving means 4 that can change the relative position of the DUT 1 with respect to the imaging means 3, and linear light obtained by the imaging means 3 A surface strain distribution calculating unit 10 is provided that performs image processing on a mirror image based on a change in relative position of the generating unit 2 and imaging unit 3 and the DUT 1 over time to calculate a strain distribution on the surface of the DUT 1. It is characterized by this.

  If the technique described in Patent Document 2 is used, design constraints for measurement conditions such as the movement of the object to be measured are surely small, and a quantitative surface strain distribution of the object to be measured can be obtained at high speed and with high accuracy. Although it may be possible to provide a surface strain measuring device and a measuring method, the linear light generating means 2 obtained by the imaging means 3 and the change in the relative position of the imaging means 3 and the DUT 1 over time can be measured. In other words, the object to be measured must be moved, so if you try to use it in actual production technology, it will take a long inspection time and the productivity will be poor. The problem which becomes is pointed out, and the solution was requested.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a surface inspection method capable of shortening the inspection time as much as possible and maintaining good productivity.

  In order to solve the above-described problems and achieve the object, a surface inspection method according to the present invention includes a first step of emitting inspection light and light emitted in the first step. The second step of transmitting the plurality of slits to obtain the striped inspection light, and passing the second step, the striped inspection light is applied to the surface of the inspection target having a specularity within a predetermined range. And a third step of irradiating with a predetermined incident angle, and a mirror image of a striped pattern is reflected on the surface of the object to be inspected, and the inspected image is observed. It is characterized by inspecting the surface condition of the object.

  Thus, by prescribing the surface inspection method according to claim 1, for inspection, it is only necessary to emit inspection light and irradiate the surface of the object to be inspected having specularity with a striped pattern. Therefore, the inspection time can be shortened as much as possible, and the remarkable effect that the productivity can be maintained satisfactorily can be obtained.

  The surface inspection method according to the present invention is characterized in that, in the first step, parallel light is used as inspection light in the first step.

  Thus, by prescribing the surface inspection method according to the second aspect, it is possible to achieve an effect that a striped pattern image is projected sharply.

  According to a third aspect of the present invention, the surface inspection method uses diffused light as the inspection light in the first step.

  Thus, by defining the surface inspection method according to claim 3, a striped pattern image can be obtained with a small amount of distortion, and an effect of improving detection accuracy can be achieved, and a striped pattern can be obtained in a wider area. An image of a pattern can be projected, and the effect that the inspection speed can be increased from this viewpoint can be achieved.

  The surface inspection method according to the present invention is characterized in that, in the second step, slits in which light transmitting portions and light non-transmitting portions are alternately arranged are used in the second step.

  Thus, by prescribing the surface inspection method according to the fourth aspect, it is possible to achieve an effect that a striped pattern can be reliably generated.

  The surface inspection method according to the present invention is characterized in that, according to claim 5, the light transmission part is defined from a space where no material exists.

  Thus, by prescribing the surface inspection method according to the fifth aspect, it is possible to achieve an effect that a slit can be easily prepared.

  According to a sixth aspect of the present invention, the surface inspection method is characterized in that the light transmission part is defined by a light transmissive material.

  Thus, by prescribing the surface inspection method according to the sixth aspect, it is possible to achieve an effect that a slit can be easily prepared.

  In the surface inspection method according to the present invention, according to the seventh aspect, in the third step, the object to be inspected is a flat surface, and from the distortion of the mirror image of the striped pattern reflected on the flat surface. The flatness of the plane is detected.

  Thus, by prescribing the surface inspection method according to claim 7, even if the object to be inspected is a flat surface, the flatness of the flat object to be inspected can be reliably detected. Will be able to.

  In the surface inspection method according to the present invention, according to the eighth aspect, in the third step, the object to be inspected is a curved surface, and from a distortion of a mirror image of a striped pattern reflected on the curved surface. , And detecting uniformity of curvature and the like over a predetermined range of the curved surface.

  Thus, by prescribing the surface inspection method according to claim 8, even if the object to be inspected is a curved surface, it is possible to surely detect the uniformity of the curvature of the curved object to be inspected. Can be played.

  According to a ninth aspect of the present invention, the surface inspection method further includes a fourth step of capturing a mirror image of a striped pattern reflected on the surface of the inspection object. .

  Thus, by specifying the surface inspection method according to the ninth aspect, the surface state of the inspection object can be obtained as data.

  According to a tenth aspect of the present invention, the surface inspection method compares the photographed image obtained in the fourth step with the golden sample image obtained in advance, and the difference therebetween. The method further includes a fifth step of determining whether the surface condition of the object to be inspected is acceptable or not.

  In this way, by defining the surface inspection method according to the tenth aspect, the state of the surface of the object to be inspected can be reliably determined as compared with the golden sample.

  As described above, according to the present invention, it is possible to provide a surface inspection method capable of shortening the inspection time as much as possible and maintaining good productivity.

  It is a figure which shows the procedure of one Example of the surface inspection method concerning this invention.   It is a figure which shows the structure which looked at the to-be-inspected object shown in FIG. 1 along the direction orthogonal to this.   It is a top view which shows the structure of the slit board shown in FIG.   It is a block diagram which shows the control system for enforcing the surface inspection method shown in FIG.   (A) is a figure which shows the striped pattern which appeared on the surface of a golden sample, (B) is a figure which shows the striped pattern which appeared on the surface with a defect.   It is a figure which shows the procedure of the other Example of the surface inspection method concerning this invention.

  Embodiments of a surface inspection method according to the present invention will be described below with reference to FIGS. 1 to 5 of the accompanying drawings.

  As shown in FIG. 1, an inspection system 10 that performs the surface inspection method of this embodiment includes an LED light emitter 12 that emits inspection light, and LED light emitted from the LED light emitter 12 as diffuse light. In order to obtain a striped inspection light by passing through the diffusion plate 14 attached immediately before the light emitter 12 and the glaze 18 on the substrate 16 to be inspected. And a slit plate 20 having a slit.

  In this embodiment, the inspection target is the surface of the glaze 18 of the partial glaze substrate 16 for the thermal head. Specifically, the surface of the glaze 18 generally formed on the ceramic substrate 16 is used. The state, i.e., whether the shape of the glaze 18 after molding is uniform along the axial direction as well as the cross-sectional shape according to predetermined specifications is inspected. Although not shown in detail, the glaze 18 is provided for the purpose of complementing the surface roughness of the ceramic substrate 16 to obtain a smooth surface and to obtain a heat storage effect. Further, as the types of glazes 18, there are a full glaze, partial glaze, light glaze, double partial glaze, full glaze, end face type, and the like. In this embodiment, the surface state of what is formed as a partial glaze is detected. Is set to

  The glaze 18 is essentially a glaze for achieving the above purpose, and exhibits a transparent property. That is, the surface of the glaze 18 as an inspection object in this embodiment has a specularity. The shape of the glaze 18 is set to have an elliptical cross section as shown in FIG. 1 and to be a long shape along the axial direction as shown in FIG.

  On the other hand, the slit plate 20 described above extends along the direction orthogonal to the optical axis of the LED light emitter 12, and the light transmitting portion 20A and the light non-transmitting portion 20B are repeated as shown in FIG. Many are formed in the state. Here, in this embodiment, the slit plate 20 itself is formed from a non-light-transmitting material that does not transmit light from the LED light emitter 12, and is defined by a long hole that penetrates the light transmitting portion 20A in the thickness direction. The light opaque portion 20B is defined from the portion between the adjacent long holes. In this embodiment, the widths of the light transmitting portion 20A and the light non-transmitting portion 20B are the same and are set to be arranged at the same pitch.

  In this embodiment, the light transmitted through the slit plate 20 is reflected in a striped pattern on the specular surface of the glaze 20 as the object to be inspected. Here, the striped pattern reflected on the mirror-like surface of the glaze 18 is photographed by the imaging camera 22, and the image data is sent to the subsequent surface state calculation circuit 24 for use in determining whether or not it is possible. It is made so that.

  Hereinafter, with reference to FIG. 4, based on the image data of the stripe pattern reflected on the surface of the glaze 18 as the object to be inspected obtained by executing this surface inspection method, the surface state calculation circuit 24, Even if the glaze 18 is used as the glaze 18 of the partial glaze substrate 16 for the thermal head, it is determined whether or not the quality of the thermal head can be maintained, and the quality is determined.

  Specifically, the surface state calculation circuit 24 includes an image input circuit 26 that receives the input of image data sent from the imaging camera 22, and the image input circuit 26 receives the input image data as a golden sample. In the case of image data obtained by photographing the stripe pattern reflected on the surface of the glaze, the golden sample image data memory 28 for storing the stripe pattern and the stripe reflected on the surface of the glaze 18 as a target for judging pass / fail In a situation where a pattern is photographed, each is connected to a detected image data memory 30 that stores the image data of the striped pattern.

  On the other hand, both memories 28 and 30 are connected to a comparison circuit 32. The comparison circuit 32 is a golden sample image data memory each time the imaging camera 22 captures a striped pattern reflected on the surface of the glaze 18. 28 is configured to capture the image data stored in advance 28 and the image data temporarily stored in the detected image data memory 30. The comparison circuit 32 is connected to a difference circuit 34. The difference circuit 34 has a predetermined detection width set along the axial direction of the glaze 18 and the two data sent from the comparison circuit 32. It is configured to take a difference.

  The difference circuit 34 is connected to a determination circuit 36. The determination circuit 36 preliminarily compares the difference between the two data output from the difference circuit 34 and a threshold setting circuit 38 connected in the same manner. When the difference between the two data is smaller than the threshold, it is determined that the inspected glaze 18 is non-defective, and when the difference between the two data is equal to or greater than the threshold, The inspected glaze is determined to be a defective product, and the determination result is sent to the output circuit 40.

  The output circuit 40 is configured to output the determination result of the determination circuit 36 to an image display device 42 configured by, for example, a liquid crystal display device, and display the determination result on the image display device 42. Yes. In this way, the operator sees the determination result in the image display device 42 to know whether the inspected glaze 18 is good or not, and those that are judged to be non-defective are transferred to the next process and are defective. The determined item is discarded in a disposal box or the like.

  Here, the striped pattern reflected on the surface of the glaze 18 as the object to be inspected by executing the procedure of the surface inspection method will be specifically shown with reference to FIG. FIG. 5A shows a striped pattern reflected on the surface of the glaze 18 as a golden sample. From this striped pattern, the pitch of the striped pattern is constant and there is no distortion in the striped pattern. From this, it can be read that there is no defect, shape defect, or flaw in the formation state of the glaze 18. On the other hand, FIG. 5B shows a “slice” or “distortion” of the stripe pattern reflected on the surface of the glaze 18 where the glaze 18 is formed. It can be read that there are some defects, shape defects, and wrinkles.

  As described above in detail, by performing the procedure of the surface inspection method of this embodiment, it is possible to determine whether or not the glaze 18 is good by simply photographing the stripe pattern reflected on the surface of the glaze 18 as the object to be inspected. In addition, if the size of the object to be inspected is within the imaging range of the imaging camera 22, only one inspection operation is required, and the inspection time is extremely short. Thus, workability can be improved.

  Moreover, even if the number of times of photographing of about 2 to 3 times is required for the entire range of the glaze 18 as an object to be inspected in consideration of the imaging range of the imaging camera 22, the imaging camera 22 is continuously connected. Therefore, since it is only necessary to take a picture while moving along the extending direction of the glaze 18, the detection time is never long and can be completed in a short time.

  It goes without saying that the present invention is not limited to the procedure of the above-described embodiment and can be variously modified without departing from the gist of the present invention.

  For example, in the above-described embodiment, a striped pattern reflected on the surface of the glaze 18 as an object to be inspected is photographed by the imaging camera 22, and the pass / fail judgment is performed by the surface state calculation circuit 24 based on this image data. However, the present invention is not limited to such a procedure, and as shown in FIG. 6 as another embodiment, fringes reflected on the surface of the glaze 18 as an object to be inspected. It goes without saying that the operator may observe the pattern with his / her own eyes and determine whether or not the stripe pattern is disordered or distorted to determine whether or not the pattern is acceptable. In short, the feature of the present invention is to irradiate slit light on the mirror-like surface of the object to be inspected, and to display a striped pattern on this surface, and to judge the quality based on the reflected striped pattern. As a main feature of the invention, whether the reflected striped pattern image is observed with the eyes of the operator or not is judged, or whether the image is taken after being captured by the imaging camera 22 and processed as image data is reversed. Does not matter.

  In the above-described embodiment, the diffused light is used as the inspection light transmitted through the slit plate 20, but the present invention is not limited to using the diffused light as described above. Needless to say, it can be inspected by using. As described above, by using parallel light as the inspection light, it is possible to obtain an effect that the edge of the striped pattern reflected on the surface of the inspection object is clearly displayed.

  In the above-described embodiment, the slit plate 20 is formed from a material that does not transmit light from the LED light emitter 12 and does not transmit light, and the light transmitting portion 20A is defined by a long hole that penetrates in the thickness direction. Although the description has been given so that the opaque portion 20B is defined from the portion between the elongated holes adjacent to each other, the present invention is not limited to such a configuration of the slit plate 20, and for example, the slit plate 20 itself The light transmitting portion 20A is defined by a portion where the material of the slit plate 20 itself is exposed, and the light non-transmitting portion 20B is formed by a thick black line printed on the surface of the slit plate 20. Needless to say, the LED light emitter 12 may be defined as a portion that does not transmit light.

  Further, while forming the slit plate 20 itself from a light-transmitting material, its entire surface is covered (or coated) with a light-impermeable material, and the light transmitting portion 20A is similar to the above-described embodiment. Needless to say, the long hole penetrating in the thickness direction may be defined, and the light-impermeable portion 20B may be defined from the portion between the long holes adjacent to each other. Further, the widths of the light transmitting portion 20A and the light non-transmitting portion 20B may be set to be different.

  In the above-described embodiment, the light transmitting portion 20A and the light non-transmitting portion 20B of the slit plate 20 have been described as having the same width. However, the present invention is limited to such a configuration. However, as a result of observing the stripe pattern projected on the actual glaze 18, even if the light transmitting portion 20 </ b> A and the light transmitting portion 20 </ b> B are set to have the same width as in the above-described embodiment, it is reflected on the glaze 18. Since the width of the dark portion of the striped pattern is narrower than the width of the light portion, the light transmission portion 20A and the light non-transmission portion 20B of the slit plate 20 are taken into consideration. It goes without saying that the widths may be set differently so that the dark and light portions projected on the glaze 18 have the same width.

  In the above-described embodiments, the LED light emitter is used as the light emitter that emits the inspection light. However, the present invention is not limited to such a configuration, and for example, halogen light emission other than the LED. It goes without saying that a vessel or the like can be used. In short, it goes without saying that anything can be used as long as it becomes slit light by passing through the slit plate 20 as inspection light.

  Further, in the above-described embodiment, it has been described that it is used to determine whether or not a partial glaze having an elliptical cross section is used. However, the present invention is not limited to such an application and is used for an inspection of a planar full-surface glaze. Needless to say, the present invention can be applied not only to the glaze inspection method but also as a method for inspecting other surface conditions.

Industrial availability

  As described above in detail, according to the present invention, the first step of emitting inspection light, and the second step of transmitting the light emitted in the first step through a plurality of slits to form striped inspection light. And a third step of irradiating the surface of the inspected object having specularity with a predetermined range and a predetermined incident angle through the step and the second step. By observing this mirror image by reflecting a mirror image of a striped pattern on the surface of the object to be inspected, the inspection time for inspecting the surface state of the object to be inspected can be shortened as much as possible. Therefore, the industrial applicability is immeasurable.

DESCRIPTION OF SYMBOLS 10 Surface inspection system 12 LED light emitter 14 Diffusion plate 16 Ceramic substrate 18 Glaze 20 Slit plate 20A Light transmission part 20B Light non-transmission part 22 Imaging camera 24 Surface state calculation circuit 26 Image input circuit 28 Golden sample image data memory 30 Inspection image data Memory 32 Comparison circuit 34 Difference circuit 36 Determination circuit 38 Threshold setting circuit 40 Output circuit 42 Image display device

Claims (10)

A first step of emitting inspection light;
A second step in which the light emitted in the first step is transmitted through a plurality of slits to form striped inspection light;
A third step of irradiating the surface of the inspected object having a specularity with a predetermined range and a predetermined incident angle through the second step. ,
A surface inspection method for inspecting a surface state of an object to be inspected by reflecting a mirror image of a stripe pattern on the surface of the object to be inspected and observing the mirror image.   The surface inspection method according to claim 1, wherein parallel light is used as inspection light in the first step.   The surface inspection method according to claim 1, wherein diffused light is used as inspection light in the first step.   The surface inspection method according to claim 2 or 3, wherein, in the second step, a slit in which light transmitting portions and light non-transmitting portions are alternately arranged is used.   The surface inspection method according to claim 4, wherein the light transmission part is defined from a space where no material exists.   The surface inspection method according to claim 4, wherein the light transmitting portion is defined by a light transmitting material.   In the third step, the object to be inspected is a plane, and the flatness of the plane is detected from the distortion of the mirror image of the striped pattern reflected on the plane. The surface inspection method according to any one of the above.   In the third step, the object to be inspected is a curved surface, and the uniformity of the curvature over a predetermined range of the curved surface is detected from the distortion of the mirror image of the striped pattern reflected on the curved surface. The surface inspection method according to any one of claims 1 to 6.   The surface inspection method according to any one of claims 1 to 8, further comprising a fourth step of capturing a mirror image of a striped pattern reflected on the surface of the inspection target.   A fifth step of comparing the photographed image obtained in the fourth step with the image of the golden sample obtained in advance and determining whether the surface condition of the object to be inspected is acceptable based on the difference is further provided. The surface inspection method according to claim 9.

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